Some good design there, bear in mind I only thend to point out the bad things ^_^
Firstly, a little top margin on the right column on the home page would be good (the borders are touching).
Make the footer (company profile, contact us...) and top navigation (home, faqs, site map) visited links remain the same as normal links, but I like that the anchors in the columns of links near the bottom have a visited style, because that helps the visitor keep track of their browsing which can be important in an e-commerce site.
Try and support noscript a little better, with the "select your gemstone" list, javascript must be enabled for the page to change. You could noscript in a submit button beside it.
As for the product lists, the blue in the product details section could be paler, and the grey in the cells to the right could also be paler. The product details cells could also do with a little more left padding. Also, whatever product that is listed at the top of the page doesn't seem to have bottom borders under the "Add to Cart" buttons, this seems to be an odd bug, not sure why that would happen.
Also there is no ' in FAQs (it's not possessive or missing a letter)
One final thing, there seems to be too heavy a use of tables to form the layout, that design would be simple with div tags instead. HTML has been used to size the images, probably adding a couple of KB to the overall file size, that could add up to a lot of bandwidth overall - I seem to be able to produce more complex layouts with about a third of the markup, it should be condensed more.